Patent literatures 1 through 5 describe a production method for the selective estrogen receptor modulator ospemifene represented by the formula (II):

Patent literature 1 describes a production method for obtaining ospemifene, wherein 4-hydroxybenzophenone and 3-chloropropiophenone are subjected to McMurry reaction to obtain the formula:
the obtained compound is alkylated with an alkylation agent represented by the formula: X—(CH2)2—O—Pr (wherein X is Cl, Br, I, methyloxy or tosyloxy, and Pr is a protective group) to obtain the formula:
which is then deprotected; and a production method for obtaining ospemifene wherein alkylation is performed with an alkylation agent represented by the formula: X—CH2—COOR (wherein X is Cl, Br, I, methyloxy or tosyloxy, and R is alkyl) to obtain the compound represented by the formula:
and then reducing this ester.
Patent literature 2 describes a production method for obtaining ospemifene through a McMurry reaction from a compound represented by the formula:
(wherein R1 represents H or C1-6 alkyl optionally substituted with one or multiple —OH groups, and R3a, R3b, R3c, R3d and R3e each independently represent H or —OH) and a compound represented by the formula:
(wherein X represents halogen or —OH, and R2a, R2b, R2c, R2d and R2e each independently represent H or —OH).
Patent literature 3 describes a production method for obtaining ospemifene wherein the formula:
(wherein Ra is C(O)—Rb, where Rb is optionally substituted phenyl) and 3-chloropropiophenone are subjected to McMurry reaction to obtain the formula:
(wherein the symbols have the same meaning as above), which is then deprotected.
Patent literature 4 describes a production method for obtaining ospemifene, wherein a compound represented by the formula:
and phenyl magnesium halide are reacted to obtain a compound represented by the formula:
which is treated with hydrochloric acid to obtain the formula:
which is then deprotected.
Patent literature 5 describes a production method for obtaining ospemifene characterized in that a perfluorophenyl group is introduced.
Furthermore, the method of producing alcohols by reacting ester and lithium borohydride is widely known.
However, patent literatures 1 through 5 do not describe or suggest a production method for ospemifene using reduction reaction by means of lithium borohydride. Furthermore, in the case of methods of producing alcohols by reacting ester and lithium borohydride, reacting in the presence of borane or reacting in the presence of trimethylsilyl chloride is not known.